Transformer oil dissolved gas degassing device and transformer oil dissolved gas detection system
By combining ultrasonic vibration, vacuum suction, and constant temperature control system inside the degassing tank, the problems of low degassing efficiency and oil contamination in existing technologies are solved, achieving efficient and simple degassing and detection of dissolved gases in transformer oil.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-04-07
AI Technical Summary
Existing transformer oil dissolved gas degassing devices have low degassing efficiency, are complex to operate, and are prone to contaminating the oil.
The system employs ultrasonic vibration, vacuum suction, and constant temperature control within the degassing tank. Degassing occurs through the oil inlet, oil outlet, air outlet, and exhaust outlet. Combined with a vacuum pump and pressure gauge, it achieves efficient degassing and avoids oil contamination.
It achieves efficient degassing of dissolved gases in transformer oil, is simple to operate, avoids oil contamination, and improves the accuracy and reliability of detection.
Smart Images
Figure CN224086078U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to transformer oil dissolved gas detection system technical field especially relates to a kind of transformer oil dissolved gas degassing device and transformer oil dissolved gas detection system. BACKGROUND
[0002] Transformer oil dissolved gas detection is mainly to effectively monitor and fault diagnosis for the running condition of oil-filled power transformer, and the dissolved gas in transformer oil needs to be degassed first, but the existing degassing device has low degassing efficiency, complex operation, and the problems such as easy to pollute oil quality. UTILITY MODEL CONTENT
[0003] The utility model at least solves one of the technical problems existing in the prior art. To this end, the utility model provides a kind of transformer oil dissolved gas degassing device, the degassing efficiency of the transformer oil dissolved gas degassing device is high, degassing mode is simple, easy to operate, and transformer oil can be avoided to be polluted.
[0004] The utility model further provides a kind of transformer oil dissolved gas detection system, including the degassing device of transformer oil dissolved gas described above.
[0005] According to the transformer oil dissolved gas degassing device of the utility model embodiment, it includes: degassing tank, the degassing tank has oil inlet, oil outlet, gas outlet and exhaust port, the degassing tank is used for degassing reaction of transformer oil, the oil inlet is communicated with the outlet of transformer oil tank, the oil outlet is communicated with the inlet of the transformer oil tank, the gas outlet is used to discharge the gas separated from transformer oil from the degassing tank, to detect the nature of the gas separated from transformer oil;Ultrasonic transducer, the ultrasonic transducer is located in the degassing tank, for ultrasonic vibration to transformer oil;Constant temperature control system, the constant temperature control system includes heating device and temperature sensor, the heating device and the temperature sensor are located in the degassing tank, the heating device is used to heat transformer oil, and the temperature sensor is used to monitor the temperature of transformer oil;Vacuum system, the vacuum system includes vacuum pump and pressure gauge, the suction port of the vacuum pump is communicated with the exhaust port of the degassing tank, and the pressure gauge is used to detect the air pressure in the degassing tank.
[0006] The utility model discloses a transformer oil dissolving gas degassing device, through having the oil inlet, oil outlet, gas outlet and exhaust port on the degassing tank, the degassing tank is used for the degassing reaction of transformer oil, and the oil inlet is connected with the outlet of transformer oil tank, and the oil outlet is connected with the import of transformer oil tank, and the gas outlet is used for the gas that separates out from transformer oil is discharged from the degassing tank to detect the nature of the gas that separates out in transformer oil, and the ultrasonic transducer is arranged in the degassing tank and is used for ultrasonic vibration to transformer oil, and the constant temperature control system includes heating device and temperature sensor, and heating device and temperature sensor are all arranged in the degassing tank, and heating device is used for heating transformer oil, and temperature sensor is used for monitoring the temperature of transformer oil, and the vacuum system includes vacuum pump and pressure gauge, and the suction of vacuum pump is communicated with the exhaust port of degassing tank, and the pressure gauge is used for detecting the air pressure in the degassing tank, thereby realizing degassing to the dissolved gas in transformer oil through ultrasonic wave, vacuum and constant temperature, and the degassing efficiency is high, and the transformer oil can be avoided being polluted, simultaneously, the degassing process is all carried out in a degassing tank, and the degassing mode is simple, and the operation is simple.
[0007] In some embodiments of the utility model, the degassing tank is a stainless steel part.
[0008] In some embodiments of the utility model, the heating device includes heating part and heat spreading plate, and the heating part is arranged in the heat spreading plate.
[0009] In some embodiments of the utility model, the oil inlet and the oil outlet are located at the lower end of the degassing tank, and the exhaust port and the gas outlet are arranged at the upper end of the degassing tank.
[0010] In some embodiments of the utility model, the ultrasonic transducer is arranged at the lower end of the degassing tank, and / or the temperature sensor is arranged at the lower end of the degassing tank, and / or the heating device is arranged at the lower end of the degassing tank.
[0011] In some embodiments of the utility model, the suction and the exhaust port have a first electromagnetic valve, and / or the oil inlet and the outlet of the transformer oil tank have a second electromagnetic valve, and / or the oil outlet and the import of the transformer oil tank have a third electromagnetic valve.
[0012] In some embodiments of the utility model, the heating device is spaced apart from the temperature sensor.
[0013] The transformer oil dissolved gas detection system according to the embodiment of the utility model, including: The above-mentioned transformer oil dissolved gas degassing device;Gas collection device, the import of gas collection device with the gas outlet of degassing device intercommunication, for collecting the gas that separates from transformer oil;Detection equipment, detection equipment is located in gas collection device, for detecting the gas property in gas collection device.
[0014] The transformer oil dissolved gas detection system according to the embodiment of the utility model, through setting above-mentioned transformer oil dissolved gas degassing device, degassing tank has oil inlet, oil outlet, gas outlet and exhaust port, degassing tank is used for the degassing reaction of transformer oil, oil inlet and the outlet of transformer oil tank intercommunication, oil outlet and the import of transformer oil tank intercommunication, gas outlet is used for the gas that separates from transformer oil exhaust degassing tank, to detect the property of gas that separates from transformer oil, ultrasonic transducer is located in degassing tank, for the ultrasonic vibration of transformer oil;Constant temperature control system includes heating device and temperature sensor, heating device and temperature sensor are located in degassing tank, heating device is used for heating transformer oil, and temperature sensor is used for monitoring the temperature of transformer oil;Vacuum system includes vacuum pump and pressure gauge, the suction of vacuum pump and the exhaust port of degassing tank intercommunication, and pressure gauge is used for detecting the air pressure in degassing tank, thereby realize the degassing of dissolved gas in transformer oil through ultrasonic wave, vacuum and constant temperature, and the degassing efficiency is high, and transformer oil can be avoided being contaminated, simultaneously, degassing process is all carried out in a degassing tank, and the degassing mode is simple, and the operation is simple.
[0015] In some embodiments of the utility model, the gas collection device is multiple, multiple gas collection devices are connected in series, and the detection equipment is multiple corresponding to the multiple gas collection devices.
[0016] In some embodiments of the utility model, one of the multiple detection equipment is a gas chromatograph detector.
[0017] The additional aspects and advantages of the utility model will be partially given in the following description, some will become obvious from the following description, or be understood by the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0018] The above and / or additional aspects and advantages of the utility model will become apparent and be readily understood from the following description, including the appended claims, taken in conjunction with the accompanying drawings, in which:
[0019] Figure 1 It is the perspective view of the transformer oil dissolved gas degassing device according to the embodiment of the utility model.
[0020] Reference signs:
[0021] 10, transformer oil dissolved gas degassing device;
[0022] 1. degassing tank; 11. oil inlet; 12. oil outlet; 13. gas outlet; 14. exhaust port;
[0023] 2. ultrasonic transducer;
[0024] 3. thermostat control system; 31. heating device; 311. heating element; 312. hot plate; 32. temperature sensor;
[0025] 4. vacuum system; 41. vacuum pump; 411. suction port; 42. pressure gauge;
[0026] 51. first solenoid valve; 52. second solenoid valve; 53. third solenoid valve;
[0027] 20. gas collection device. DETAILED DESCRIPTION
[0028] The embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for the purpose of explaining the present application, and cannot be understood as limiting the present application.
[0029] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the features limited as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0030] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0031] The following is for reference. Figure 1 Describes a transformer oil dissolved gas degassing device 10 according to an embodiment of the present invention.
[0032] like Figure 1 As shown, the transformer oil dissolved gas degassing device 10 according to an embodiment of the present invention includes: a degassing tank 1, an ultrasonic transducer 2, a constant temperature control system 3, and a vacuum system 4.
[0033] Specifically, refer to Figure 1 The degassing tank 1 has an oil inlet 11, an oil outlet 12, a gas outlet 13, and a vent 14. The degassing tank 1 is used for degassing transformer oil. The oil inlet 11 is connected to the outlet of the transformer oil tank, the oil outlet 12 is connected to the inlet of the transformer oil tank, and the gas outlet 13 is used to discharge the gas precipitated from the transformer oil into the degassing tank 1 to detect the properties of the gas precipitated from the transformer oil.
[0034] It should be noted that internal transformer faults typically cause localized overheating or discharge. These abnormalities lead to the decomposition of transformer oil and solid insulation materials, generating various gases, most of which dissolve in the transformer oil. Detecting the composition and content of these dissolved gases in the transformer oil can determine whether an internal fault exists, its type, and its severity. By taking a portion of transformer oil into degassing tank 1 and conducting a degassing reaction within it, the dissolved gases in the transformer oil are removed. The oil is then discharged from degassing tank 1 through exhaust port 14 and proceeds to subsequent testing procedures to determine the properties (composition and content) of the gases.
[0035] Furthermore, such as Figure 1 As shown, the ultrasonic transducer 2 is installed inside the degassing tank 1 and is used to subject the transformer oil to ultrasonic vibration. It should be noted that the transformer oil dissolved gas degassing device 10 also includes an ultrasonic generator, which generates a high-frequency electrical signal to drive the ultrasonic transducer 2. The ultrasonic transducer 2 converts the high-frequency electrical signal into mechanical vibration, generating ultrasonic waves (ultrasonic frequency of 20kHz-100kHz). This achieves high degassing efficiency by using ultrasound to degas the dissolved gas in the transformer oil.
[0036] Furthermore, such as Figure 1As shown, the constant temperature control system 3 includes a heating device 31 and a temperature sensor 32. Both the heating device 31 and the temperature sensor 32 are located inside the degassing tank 1. The heating device 31 is used to heat the transformer oil, and the temperature sensor 32 is used to monitor the temperature of the transformer oil. The heating device 31 heats the transformer oil, and the temperature sensor 32 detects the temperature, thereby keeping the transformer oil at a suitable temperature. At the appropriate temperature, the viscosity of the transformer oil decreases, its fluidity increases, and gas is more easily separated from the transformer oil, which helps to improve the efficiency of the degassing process.
[0037] In addition, the constant temperature control system 3 can prevent the oil from being subjected to thermal stress due to temperature fluctuations during the degassing process, thereby protecting the chemical and physical properties of the oil. Specifically, the constant temperature control system 3 controls the temperature inside the degassing tank 1 to be 49-51℃.
[0038] Furthermore, such as Figure 1 As shown, the vacuum system 4 includes a vacuum pump 41 and a pressure gauge 42. The suction port 411 of the vacuum pump 41 is connected to the exhaust port 14 of the degassing tank 1, and the pressure gauge 42 is used to detect the gas pressure inside the degassing tank 1. The vacuum pump 41 is used to extract the gas from the degassing tank 1, and the pressure gauge 42 is used to detect whether the gas pressure inside the degassing tank 1 has reached a preset value. For example, in this invention, the preset gas pressure is 10-1000 Pa, thereby achieving a vacuum state inside the degassing tank 1. Under vacuum conditions, the partial pressure of dissolved gases in the transformer oil decreases, and the gas is more likely to escape from the transformer oil, thereby further improving the degassing efficiency.
[0039] In addition, the degassing tank 1 is first evacuated by vacuum pump 41 before the transformer oil is fed into it. On the one hand, the vacuum environment inside the degassing tank 1 makes it easier for the transformer oil to enter, improving the oil intake efficiency. On the other hand, the vacuum environment inside the degassing tank 1 prevents the transformer oil from coming into contact with air, thus preventing the transformer oil from being contaminated.
[0040] Furthermore, the degassing process is carried out entirely within a degassing tank 1, making the degassing method simple and the operation easy.
[0041] According to the embodiment of the present invention, the transformer oil dissolved gas degassing device 10 has an oil inlet 11, an oil outlet 12, a gas outlet 13, and an exhaust outlet 14 on the degassing tank 1. The degassing tank 1 is used for degassing the transformer oil. The oil inlet 11 is connected to the outlet of the transformer oil tank, the oil outlet 12 is connected to the inlet of the transformer oil tank, and the exhaust outlet 13 is used to discharge the gas extracted from the transformer oil into the degassing tank 1 to detect the properties of the gas extracted from the transformer oil. An ultrasonic transducer 2 is installed in the degassing tank 1 to perform ultrasonic vibration on the transformer oil. The constant temperature control system 3 includes a heating device 31 and a temperature sensor 32, both of which are installed in the degassing tank 1. The heating device 31 is used to heat the transformer oil, and the temperature sensor 32 is used to monitor the temperature of the transformer oil. The vacuum system 4 includes a vacuum pump 41 and a pressure gauge 42. The suction port 411 of the vacuum pump 41 is connected to the exhaust outlet 14 of the degassing tank 1, and the pressure gauge 42 is used to detect the gas pressure in the degassing tank 1. This method achieves degassing of dissolved gases in transformer oil using ultrasound, vacuum, and constant temperature, resulting in high degassing efficiency and preventing transformer oil contamination. Furthermore, the entire degassing process is carried out within a single degassing tank (1), making the degassing method simple and easy to operate.
[0042] In some embodiments of this utility model, the degassing tank 1 is made of stainless steel. It is understood that stainless steel contains chromium, which forms a dense chromium oxide protective film on its surface, effectively resisting corrosion from air, moisture, acids, alkalis, salts, and other media. Simultaneously, stainless steel possesses good mechanical properties, as well as good high-temperature stability and low-temperature toughness, thus making the degassing tank 1 corrosion-resistant, high-temperature resistant, and structurally stable, resulting in a long service life.
[0043] In some embodiments of this utility model, such as Figure 1 As shown, the heating device 31 includes a heating element 311 and a heat spreader 312, with the heating element 311 disposed within the heat spreader 312. It can be understood that the heating element 311 can be a heating wire, which extends meanderingly within the heat spreader 312. The heat spreader 312 ensures that the transformer oil is heated evenly, preventing uneven heating and allowing the constant temperature control system 3 to better control the transformer oil temperature, thus improving degassing efficiency.
[0044] In some embodiments of this utility model, such as Figure 1 As shown, the oil inlet 11 and oil outlet 12 are both located at the lower end of the degassing tank 1, while the exhaust port 14 and air outlet 13 are both located at the upper end of the degassing tank 1. It is understandable that gas, with its lower density, tends to rise. The location of the oil inlet 11 and oil outlet 12 at the lower end of the degassing tank 1, and the air outlet 13 at the upper end, prevents the gas from mixing with the transformer oil again, thus improving degassing efficiency. The exhaust port 14 at the upper end of the degassing tank 1 improves the efficiency of vacuuming.
[0045] In some embodiments of this utility model, such as Figure 1 As shown, the ultrasonic transducer 2 is located at the lower end of the degassing tank 1; thus, the ultrasonic transducer 2 can be easily immersed in the transformer oil, thereby further improving the degassing efficiency.
[0046] In some embodiments of this utility model, such as Figure 1 As shown, the temperature sensor 32 is located at the lower end of the degassing tank 1; thus, the temperature sensor 32 can be immersed in the transformer oil, thereby enabling the temperature sensor 32 to better detect the temperature of the transformer oil, control the temperature of the transformer oil to be constant, and further improve the degassing efficiency.
[0047] In some embodiments of this utility model, such as Figure 1 As shown, the heating device 31 is located at the lower end of the degassing tank 1. This allows the heating device 31 to be immersed in the transformer oil, thereby further improving the heating efficiency and preventing the heating device 31 from burning dry.
[0048] In some embodiments of this utility model, such as Figure 1 As shown, a first solenoid valve 51 is provided between the suction port 411 and the exhaust port 14, thereby controlling the vacuuming process and its stopping.
[0049] In some embodiments of this utility model, such as Figure 1 As shown, a second solenoid valve 52 is provided between the oil inlet 11 and the outlet of the transformer oil tank; thereby, the oil inlet can be controlled to proceed and stop.
[0050] In some embodiments of this utility model, such as Figure 1 As shown, a third solenoid valve 53 is located between the oil outlet 12 and the inlet of the transformer oil tank. This allows for the control of oil discharge.
[0051] In some embodiments of this utility model, such as Figure 1 As shown, the heating device 31 and the temperature sensor 32 are spaced apart. This avoids interference from the instantaneous power of the heating device 31 during heating with the measurement of the temperature sensor 32, making the measurement of the temperature sensor 32 more accurate and reliable.
[0052] The following describes a transformer oil dissolved gas detection system according to an embodiment of the present invention.
[0053] The transformer oil dissolved gas detection system according to an embodiment of the present invention includes: the above-mentioned transformer oil dissolved gas degassing device 10, gas collection device 20, and detection device. The inlet of the gas collection device 20 is connected to the outlet 13 of the degassing device and is used to collect the gas precipitated from the transformer oil. The detection device is located in the gas collection device 20 and is used to detect the properties of the gas in the gas collection device 20.
[0054] A control valve is provided between the transformer oil dissolved gas degassing device 10 and the gas collection device 20 to facilitate the control of gas entering the gas collection device 20 from the transformer oil dissolved gas degassing device 10.
[0055] According to the transformer oil dissolved gas detection system of this utility model embodiment, by setting the above-mentioned transformer oil dissolved gas degassing device 10, the degassing tank 1 has an oil inlet 11, an oil outlet 12, a gas outlet 13, and an exhaust port 14. The degassing tank 1 is used for degassing the transformer oil. The oil inlet 11 is connected to the outlet of the transformer oil tank, the oil outlet 12 is connected to the inlet of the transformer oil tank, and the exhaust port 13 is used to discharge the gas precipitated from the transformer oil into the degassing tank 1, so as to detect the properties of the gas precipitated from the transformer oil. An acoustic transducer 2 is installed inside the degassing tank 1 to perform ultrasonic vibration on the transformer oil. A constant temperature control system 3 includes a heating device 31 and a temperature sensor 32, both located inside the degassing tank 1. The heating device 31 heats the transformer oil, and the temperature sensor 32 monitors the oil temperature. A vacuum system 4 includes a vacuum pump 41 and a pressure gauge 42. The suction port 411 of the vacuum pump 41 is connected to the exhaust port 14 of the degassing tank 1, and the pressure gauge 42 detects the gas pressure inside the degassing tank 1. This achieves degassing of dissolved gases in the transformer oil through ultrasound, vacuum, and constant temperature control, resulting in high degassing efficiency and preventing transformer oil contamination. Furthermore, the entire degassing process is carried out within a single degassing tank 1, making the degassing method simple and easy to operate.
[0056] In some embodiments of this invention, there are multiple gas collection devices 20 connected in series, and multiple detection devices corresponding one-to-one with each of the gas collection devices 20. This allows for more accurate detection of dissolved gases in transformer oil, improving the reliability and accuracy of the detection.
[0057] In some embodiments of this invention, one of the multiple detection devices is a gas chromatograph detector. It is understood that gas chromatograph detectors are simple in structure, stable in performance, have a wide linear range, respond to both inorganic and organic compounds, and do not damage the sample, thus facilitating simple, rapid, and effective identification of dissolved gases in transformer oil.
[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0059] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A transformer oil dissolved gas degassing device, characterized in that, include: A degassing tank has an oil inlet, an oil outlet, a gas outlet, and an exhaust port. The degassing tank is used for degassing transformer oil. The oil inlet is connected to the outlet of the transformer oil tank, the oil outlet is connected to the inlet of the transformer oil tank, and the gas outlet is used to discharge the gas precipitated from the transformer oil into the degassing tank to detect the properties of the gas precipitated from the transformer oil. An ultrasonic transducer is provided inside the degassing tank and is used to subject the transformer oil to ultrasonic vibration. A constant temperature control system includes a heating device and a temperature sensor, both of which are located inside the degassing tank. The heating device is used to heat the transformer oil, and the temperature sensor is used to monitor the temperature of the transformer oil. A vacuum system, comprising a vacuum pump and a pressure gauge, wherein the suction port of the vacuum pump is connected to the exhaust port of the degassing tank, and the pressure gauge is used to detect the gas pressure inside the degassing tank.
2. The transformer oil dissolved gas degassing device according to claim 1, characterized in that, The degassing tank is made of stainless steel.
3. The transformer oil dissolved gas degassing device according to claim 1, characterized in that, The heating device includes a heating element and a heat spreader plate, wherein the heating element is disposed in the heat spreader plate.
4. The transformer oil dissolved gas degassing device according to claim 1, characterized in that, The oil inlet and the oil outlet are both located at the lower end of the degassing tank, while the exhaust port and the air outlet are both located at the upper end of the degassing tank.
5. The transformer oil dissolved gas degassing device according to claim 4, characterized in that, The ultrasonic transducer is located at the lower end of the degassing tank; And / or, the temperature sensor is located at the lower end of the degassing tank; And / or, the heating device is located at the lower end of the degassing tank.
6. The transformer oil dissolved gas degassing device according to claim 1, characterized in that, A first solenoid valve is provided between the suction port and the exhaust port; And / or, a second solenoid valve is provided between the oil inlet and the outlet of the transformer tank; And / or, a third solenoid valve is provided between the oil outlet and the inlet of the transformer tank.
7. The transformer oil dissolved gas degassing device according to claim 1, characterized in that, The heating device is spaced apart from the temperature sensor.
8. A transformer oil dissolved gas detection system, characterized in that, include: Transformer oil dissolved gas degassing device according to any one of claims 1-7; A gas collection device, wherein the inlet of the gas collection device is connected to the outlet of the degassing device, is used to collect the gas precipitated from the transformer oil; A detection device is provided in the gas collection device and is used to detect the properties of the gas in the gas collection device.
9. The transformer oil dissolved gas detection system according to claim 8, characterized in that, There are multiple gas collection devices connected in series, and there are multiple detection devices corresponding one-to-one with each of the gas collection devices.
10. The transformer oil dissolved gas detection system according to claim 9, characterized in that, One of the plurality of detection devices is a gas chromatograph detector.